mac80211: fix failure to check kmalloc return value in key_key_read

I noticed two small issues in mac80211/debugfs_key.c::key_key_read while
reading through the code. Patch below.

The key_key_read() function returns ssize_t and the value that's actually
returned is the return value of simple_read_from_buffer() which also
returns ssize_t, so let's hold the return value in a ssize_t local
variable rather than a int one.

Also, memory is allocated dynamically with kmalloc() which can fail, but
the return value of kmalloc() is not checked, so we may end up operating
on a null pointer further on. So check for a NULL return and bail out with
-ENOMEM in that case.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/debugfs_key.c b/net/mac80211/debugfs_key.c
index 4aa47d0..1243d1d 100644 (file)
--- a/net/mac80211/debugfs_key.c
+++ b/net/mac80211/debugfs_key.c
@@ -203,9 +203,13 @@ static ssize_t key_key_read(struct file *file, char __user *userbuf,
                            size_t count, loff_t *ppos)
 {
        struct ieee80211_key *key = file->private_data;
                            size_t count, loff_t *ppos)
 {
        struct ieee80211_key *key = file->private_data;

-       int i, res, bufsize = 2 * key->conf.keylen + 2;
+       int i, bufsize = 2 * key->conf.keylen + 2;

        char *buf = kmalloc(bufsize, GFP_KERNEL);
        char *p = buf;
        char *buf = kmalloc(bufsize, GFP_KERNEL);
        char *p = buf;

+       ssize_t res;
+
+       if (!buf)
+               return -ENOMEM;

 
        for (i = 0; i < key->conf.keylen; i++)
                p += scnprintf(p, bufsize + buf - p, "%02x", key->conf.key[i]);
 
        for (i = 0; i < key->conf.keylen; i++)
                p += scnprintf(p, bufsize + buf - p, "%02x", key->conf.key[i]);